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PATENT OEEICE.

HENRY W. METZING, OF NEW YORK, N. Y.

PNEUMATIC ENGINE.

SPECIFICATION formingpart of Letters Patent No. 417,493, dated December 17, 1889.

` l Application filed September 12, 1889. Serial No. 323,710. (No model.)

To all whom it may concern;

Be it known that I, HENRY W. METZING, a citizen of the United States, residing at New York, in the county of New York and State ofN ew York, have invented new and useful Improvements in Pneumatic Engines, of which the following is a specification.

This invention relates to a pneumatic engine suitable for various purposes, such as actuating dental and other tools; and the invention consists in the details of construction set'forth in the following specification and claims, and illustrated in the acccompanying drawings, in which- Figure l is a plan view, partly in section, of a motor. Fig. 2 is a view similar to Figui, with parts in a different position than Fig. 1. Fig. 3 is a longitudinal section of the motor alonga: x, Fig. 4. Fig. 4 is a section of the Fig. 5 is a detail view of the cylinder.

Similar letters indicate corresponding parts.

In the drawings, the letter A indicates a casing which incloses the cylinderB and the main-valve chamber C. The supply-channel D leads into the valve-chamber, and E is the exha ust-channel leading from the valve-chamber. The valve-chamber is provided with the main valve F, and from the valve-chamber lead the ports b b to the opposite ends of the cylinder B. The valve F is shown in form of a disk having some portions cut away, Figs. 1 and 2, and said valve has two gudgeons cc', one of which engages with a suitable cavity in the valve-chamber, while the other engages with a cavity in the cap G. Said cap closes the valve-chamber and is retained in place by the casing or shell A.

The valve F receives motion from a pin c, which extends through a slot f in the valvechamber and engages with a cavity or depression g (shown in broken lines, Figs. 3 and 4) in the piston H. When said piston is at one end of its stroke, the valve F occupies the position shown in Fig. l. If air under pressure is now introduced through the supply-channel D, this air passes into the cylinder through port b', and the piston is driven forward or to the position shown in Fig. 2, the air in front of the piston escaping through the exhaustport E. As the piston approaches the end of its forward stroke the valve is moved to the position shown in Fig. 2, the compressed air passes into the cylinder through the port b, and the piston is driven backward or from the position shown in Fig. 2, while the air at the back of the piston is driven out through the exhaust-port E.

From the casing A extends a hollow shank I, forming the guide for the piston-rod. This piston-rod is reciprocated bythe pist-on and can be provided at its free end with any suitable `tool-such'as a tracer-for making punctures into a suitable surface, or with a dental plugger or other tool.

, The outer face of the cylinder B is provided with channels J K. The piston H has channels L M and cushioning-valve chambers L M, provided with cushioning-valves N, having springs which normally move said valves to the position to close the channels L M. Stems O project from said valves beyond the piston. When the pistons near the end of a stroke, (for example, its forward stroke,) the channel L is opened, Fig. 3, by the corresponding valve N being moved through its stem O, striking the cylinder-head. Oompressed air then passes from channel J into channel L', and through valve-chamber L into the space between the front of the piston and the cylinder, thus forming a` cushion which prevents the piston front from slamming against the cylinder. When the piston nears the end of its backward stroke, the channel M is opened, so that air passing through the channels K M forms a cushion which prevents the back of the piston from slamming against the cylinder-head. The channels J K lead from the space between the shell Aand cylinder B to their respective channels L M in the piston. The course of one channel (the channel K) is plainly shown in Fig. 4. At their inner mouths the channels J K have enlargements J K', so that communication is readily obtained between the channels J K and channels L M.

What I claim as new, and desire to secure by Letters Patent, is-

l. The combination of a casing A, havinga supply-channel D at one side and an exhaustchannel E at another side,a cylinder 13,10- cated within the casing between the supply IOO with channels J K, communicating with said channels L M', said cylinder having the supply and exhaust clumne1s,the ports, and main Valve, and being inelosed by a suitable casing, substantially as described.

In Iestimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

HENRY XV. METZING.

Witnesses:

WM. C. HAUFF, ERNST F. KASTENHUBER, 

